a. the red root of this vine
b. a red dye made from this; see also alizarin
4. designating a family (Rubiaceae, order Rubiales) of chiefly tropical, dicotyledonous
herbs, shrubs, and trees, including bedstraw, bluet, coffee, and cinchona
Webster’s New World College Dictionary, Fourth Edition, compiled by the
editors of Webster’s New World Dictionaries. Copyright © 2010 by Houghton
Mifflin Harcourt. Published by Houghton Mifflin Harcourt. All rights reserved.
Word origin of 'madder'ME mader < OE mædere, akin to ON mathra, Norw modra < IE base *modhro-, dye plant > Czech modrý, blue